Alert threshold for nitrogen dioxide
2.2 400 μg/m3 measured over three consecutive hours at locations representative of air quality over at least 100 km2 or an entire zone or agglomeration, whichever is the smaller.
2.2 400 μg/m3 measured over three consecutive hours at locations representative of air quality over at least 100 km2 or an entire zone or agglomeration, whichever is the smaller.